There's a limit to how effectively dental fillings can fill large cavities, but this isn't always entirely clear. It's not as though the dentists in your local practice won't make a specific recommendation, but sometimes it's a matter of choosing between trying to correct a large cavity with a filling or by avoiding a traditional filling altogether by using a dental crown. What are some of the factors that will influence the final decision?

The Size of the Cavity

It's important to understand the difference between how the size of the cavity determines the success of a filling. Smaller cavities are closed with a filling material, and the relatively small size of the breach means that the filling material is seamlessly integrated into the tooth's structure. It's small enough that, for all intents and purposes, it becomes part of the tooth. 

The Tooth's Structure

With a larger cavity, the application of the necessary amount of material to fill the breach will alter the tooth. The tooth's structural integrity is in question because a significant portion of its surface material is now made up of the filling material. In the short term, this is unlikely to cause complications. However, in the months and years to come, the constant exposure to pressure (via the force of your bite) can destabilise the section of the tooth covered by the filling material, compromising the strength of the entire tooth. The filling can act as a type of wedge between the remaining portions of the tooth, and when the tooth is exposed to bite pressure, these opposing forces can work against each other, pressing against the filling, leading to these portions cracking. Additionally, the filling can crack or loosen and can detach.

Dental Crowns

This is why larger fillings are often corrected with a dental crown, which encases the entire tooth. This corrects the cavity while strengthening the structural integrity of the tooth. There may be instances when a dentist will tell you that a dental crown is preferable, but that a large filling might still be effective. Your dentist won't always make the final decision for you, as they realise that there's a considerable price increase between a filling and a crown.

Opting for a Filling

If you opt for a filling, it's important to acknowledge that this might not be the permanent fix you were hoping for. This means you must be aware that a large filling may fail, and as such, it may need to be replaced with a crown at a later stage. If the failure has resulted in further cracking of the tooth, the crown will rectify this issue by fully encasing the damaged tooth in a robust porcelain cap, which restores the tooth to full functionality.

You should certainly ask your dentist's recommendation when it comes to choosing between a crown and a large filling, and if your finances allow it, opting for a crown can be the wisest choice. Reach out to a dentist in your area to learn more.